Earth formations may be used for various purposes such as hydrocarbon production, geothermal production, and carbon dioxide sequestration. Boreholes are drilled into the earth using drilling rigs in order to access the formations.
Drilling automation using the drilling rigs requires more and more monitoring of tasks to acquire information about the drilling process. Monitoring the rig floor of a drilling rig and obtaining information about surface dynamics of a drill string is a substantial part of drilling automation. Hence, it would be well received in the drilling industry if apparatus and method could be developed to improve the reliability of obtaining information of interest about the drill string.